When we first articulated ObamaCare’s fundamental constitutional flaws in these pages nearly two years ago, our objections were met with derision by the law’s defenders. Those who have been following the unfolding litigation are no longer laughing.

Three U.S. Circuit Courts of Appeals are poised to render decisions on the Patient Protection and Affordable Care Act in the coming months. Despite hundreds of briefing pages and numerous oral arguments, government lawyers have yet to address the law’s most basic constitutional infirmity. Only a “general police power”—the right to enact laws alleged to be in the public interest without regard to interstate commerce or some other federal legislative authority—can support the law’s centerpiece, the “individual mandate” that all Americans purchase health insurance. The Constitution denies that power to the federal government, reserving it to the states alone.

In enacting the individual mandate, Congress purported to rely on its power to regulate interstate commerce and, in the process, reach individuals who are already engaged in that commerce. But the individual mandate does not regulate commerce, interstate or otherwise. It simply decrees that all Americans, unless specially exempted, must have a congressionally prescribed level of health-insurance coverage regardless of any economic activity in which they may be engaged. Requiring individuals to act simply because they exist is the defining aspect of the general police power that Congress lacks.

The government’s lawyers, recognizing this fundamental constitutional reality, have tried to rewrite the law so that it can withstand judicial scrutiny. They have claimed that the individual mandate is a tax, despite common sense, judicial precedent, and numerous statements to the contrary by the law’s sponsors and President Obama. They have also argued that ObamaCare does not actually impose a mandate on inactive citizens, but rather regulates how individuals will pay for their health care. As Solicitor General Neal Katyal recently put it, the mandate is “about failure to pay, not failure to buy.” This is plainly wrong. The law requires that everyone have health insurance—without regard to whether or how they buy or pay for medical services.

Congress, of course, could regulate how actual, not hypothetical, health care is bought or paid for. There are also ways in which Congress could, constitutionally, achieve the near-universal health-care coverage it sought by passing ObamaCare. Most directly, it could raise taxes to pay for universal coverage. But this option would carry far higher political costs than the scheme Congress actually adopted, which effectively shifts the costs (and ultimately the inevitable need to raise taxes) to the states.

That’s why ObamaCare is so constitutionally pernicious. Our Framers adopted a dual-sovereignty architecture, dividing powers between the national government and the states. As Supreme Court Justice Anthony Kennedy explained in United States v. Lopez (1995), this division achieves two goals. It protects individual liberty, and it ensures that voters can identify which level of government is responsible for what policies so that a proper accounting can be made at the ballot box.

Consistent with the fundamental principle that the federal government is one of limited, enumerated powers, more than 220 years of case law requires that exercises of the commerce power be grounded in a meaningful, judicially enforceable, limiting principle. ObamaCare’s defenders can’t articulate such a principle.

They began with the claim that there was no difference between activity and inactivity, since both involved decisions, and thus could be reached under the commerce power. Having largely abandoned this unwinnable argument, they now claim that the mandate does not really compel individuals to buy insurance, but merely regulates their inevitable future health-care consumption.

But because the future consumption of nearly all existing goods and services is inevitable across the entire population, this argument means that Americans can then be compelled to purchase an infinite variety of goods and services chosen by Washington. Far from limiting what government can do, this is the ultimate enabling principle. Even Soviet apparatchiks, who told producers what to make, did not dare tell people what to buy.

ObamaCare’s defenders have sought to manufacture another limiting principle. They claim that health care is unique because everyone will use medical services, health-care costs can be financially ruinous for uninsured individuals, and others will then have to pick up the slack by subsidizing consumers who do not pay their medical bills. Yet any number of national markets, including the housing market, share these same characteristics.

Thus the administration’s position comes to this: What is one unconstitutional law, more or less, among friends? Health care is simply more important than any other issue. And Congress can be trusted to act responsibly, imposing purchase mandates only when they are essential. That’s why Congress can mandate medical insurance but would never require Americans to buy broccoli. The courts have always found such promises constitutionally insufficient.

The courts will also see through claims by ObamaCare supporters that the law’s opponents are trying to “re-litigate” the New Deal. The New Deal is not at issue. Both before and after the Supreme Court accepted the constitutionality of federal economic regulations in the late 1930s, it has consistently stated that there are limits on federal power and, in particular, on Congress’s power to regulate interstate commerce. It has upheld those limits in a number of cases, making clear that federal regulation cannot reach into areas too remote from legitimate federal concerns.

If ObamaCare is to be upheld, then the Supreme Court will have to abandon these precedents, along with the plain meaning of the Constitution. It will also have to concede that our federal system is in fact not one of divided authority between federal and state governments, but one in which the states merely act as Washington’s administrative enforcers. There is every reason to believe the court would never entertain such a notion.